Steplessly variable speed-changing gear



Dec. 6, 1949 E. KOLLER 2.490525 ST EPLESSLY VARIABLE SPEED-GHANGING GEAR Filed July 8, 1946 Patented Dec. 6, 1949 2,490,525 STEPLESSLY VARIAII3ELE SPEED-CHANGING G AB Emil Koller, Zurich, Switzerland, assignor to Dabo Ltd., Zug, Switzerland Application July 8, 1946, Serial No. 681,872 In Switzerland May 10, 1946 3 Claims.

Steplessly variable speed-changing gears are known in the art, in which the torque is transmitted solely by frictional forces. The positive operation of such gears is uncertain, particularly at overloads, due to slippage, and their wear is excessive, which deficiencies alone render their application in many cases practically impossible. Such frictional change-speed gears, moreover, only may be applied for limited power transmission, and necessitate comparatively great structural dimensions even for relatively small torques. Such latter circumstance also holds true for change-speed gears operating by means of V- belts or special chains, as well as for all kinds of hydraulic speed-changing gears. A further disadvantage of all speed-changing gears is the comparatively small regulating range, limited by their mode of operation.

The object of my present invention is to eliminate such disadvantages. To this end, my present invention of a steplessly variable speedchanging gear comprises rollers for producing a blocking action, disposed annularly between adjacent or opposite rotary discs, i. e. mounted on the one disc and only contacting the other disc in a given circular track thereof. The two rotary discs are positively engaged with each other by virtue of the locking action set up by the rollers; and the transmission ratio may be varied by radially acting adjusting means.

The structure of my present invention affords, in a comparatively simple Way and manner, a compact design of the speed-changing gear even in case of a great regulating range. Fundamentally, there is no restriction as to the magnitude of the power transmission. Various forms of invention are illustrated, partly schematically, in the accompanying drawing, in which:

Fig. 1 shows a first form in elevation,

Fig. 2, in larger scale, the mounting of the rollers in a partial side view, and in section,

Fig. 3 a second form in elevation, partly in section,

Fig. 4, in larger scale, the mounting of the rollers, in part elevation,

" Fig. 5 a third form in elevation, partly in section,

Fig. 6 a fourth form in axial section, and

Fig. '7 a portion of a further form, in axial section.

In Fig. l, the shaft I, mounted in the frame 2, has a disc 3 secured to its shown end, and the operating face 4 of the disc 3 is perfectly plane. A guide spindle 5 is disposed parallel to the said face 4 and, therefore, at right angles to the shaft I. A bearing block 6 for a stub shaft I is disposed displaceably on the spindle 5. A disc 8, facing the disc 3, is secured to one end of the stub shaft I, and its surface opposite the face 4 is provided with a plurality of recessed seats 9 for a ball II) each. The seats 9 are circularly disposed, concentric with the stub shaft 1; and the balls II) are retained on the rotary disc 8 by a cage not shown. The stub shaft 7 is in engagement with a telescope shaft I 2 by means of a universal joint II, and the shaft I2 is connected to a shaft I4 through the intermediary of a second universal joint I3. The last-mentioned shaft I4 is mounted rotatably in the frame '2, coaxial with the shaft I. The displaceable bearing block 6 is engaged by the spindle 5, by means of threads I5, so that, upon rotating the spindle, the disc 8 may be displaced relative to the disc 3, that is radially adjusted relative to the axis I-I4, the telescope shaft I2 automatically being adjusted in length as required.

As shown in Fig. 1, the disc 8 is inclined rela tive to the disc 3, and the balls I I] of the skew disc 8 thus contact the face 4 of the disc 3 along a circular track concentric to the shaft I. The skew disc 8 is of substantially smaller diameter than the disc 3. The recessed ball seats 9 on the skew disc 8 are formed, according to Fig. 2, by longitudinal recesses tapered endwise, wherein the balls I0 are guided circumferentially on the disc 8 with certain limited play in either sense of rotation of the latter.

When, now, from the shaft I I the skew disc 8 is driven in the one or other direction of rotation, the balls I0 become seized in their seats in the given circular track on the face t, thus positively engaging the two rotary discs 3 and 8 which, of course, are secured against axial displacements. Such engagement is afforded by virtue of the incoming torque producing a locking action between the two rotary discs 3 and 8 through the intermediary of the balls It, which locking action always corresponds in magnitude to the power to be transmitted at any one time. The transmission ratio may be steplessly varied, within given limits, by radially displacing the stub shaft 1 and. the skew disc 8 relative to the disc 3, as will be readily appreciated.

In the form of invention shown in Fig. 3, a

disc I6 is secured to the stub shaft '5, and the disc I! disposed beside the disc I6 is parallel to the latter and secured to the shaft I. The disc If is provided with radial grooves I a which form seats for the balls II The latter are retained by a ring I9 in the said grooves I8 which are tapered in cross-section toward the longitudinal brims, v

and the said ring is provided with a curved guide slot for each ball Ill.

By turning the ball cage [9 relative to the rotary disc [1, the radial distance of the balls in from the axis l-l4 may be varied for the purpose of changing thetransinis'sionjratio. 7

Elements of the form of invention shown in Figs. 1 and 2, are used in the structure according to Fig. 5. The two parallel discs 3 and 8; provided with recessed seatsfor the balls ill, together with the coaxial shafts l and 1, are mounted in a case 21. The balls 10 appurtenant to each disc 3 and 8, are retained cages 22; A skew disc 23, provided with plane faces; is rotatably mounted in a ring 24 by n 1eansof balls 25, intermediate of the discs 3 and 82. The ring 24 is displaceable, by means of an adjusting device, in a guide slot 26 in the plane of the skew disc 23, which latter is so positioned as on either face a ball l9 each of the two discs 3 and 8, the said two balls lfl' or, respectively, the points of contact defined thereby being" dia'met rically opposite each other. The axis of the skew disc 23 is denoted by 21. p

. When the latter coincides with the axis l-'l, the transmission ratio is- 1:1 or 1". When, however, the ring 24 with the skew disc 23 is dis placed from such position, its axis 21 is moved toward or away from the axis l--1, and a corre'-' sponding effective difference of radiusof the two diametrically opposite contact balls I9 is set up so that the transmission ratio between the discs 3 and 8 may be steple'ssly varied in one sense or the other. Y

In Fig. 6, the one shaft again is denoted by' l, and the disc 3 is provided withrecessed seats for balls in retained and guided the cage 22'. The disc 3 is secured against rotation on the shaft l by the key 28. The skew disc 23' is' disposed intermediate of the rotary dis'g and a flanged rotary disc 29, and is" provided with a central aperture for the passage of the shaft i The disc 29 is provided with recessedseats Elfor balls [0 guided in another cage 22'. The disc 29 is provided with an inside ri'1n gear 30 and mounted rotatable on the shaft I, and a central spur gear wheel 32 is securdto the' latter by a key 3|. A planet wheel 33 engages the central spur wheel 32, and its pivot 34 n ounted in the is secu'red to the shaft bearing structure 35 which 36 coaxial with the shaft l by a key 31 7 When the shaft l rotates at constant speed, the operation of the change-speed gear is as fol-' lows:

I As described with reference to the speed between the discs 3 and 29 may be varied in the form of invention shown in Fig. ,6 by fneans of the skew disc 23. The speed of the rim gear 30 relative to that of the central wheel 32 may be varied positively or negatively ie. leading or lagging, by rolling off the planet wheel intermediate of the gear wheels 30 and 32 irl the one sense of rotation or the other. Thespeed of the pivot 34 or of the shaft 36 respectively; is composed of the speed of the shaftl and the rela-' tive speed of the planet wheel 33, which may be positive or negative. By correspondingly selecting the relative dimensions of the gear elements inquestion, therefore, the speed of the" shaft 36 may be reduced to zero or the resulting rotation reversed.

In the form of invention shown in Fig. 7, the

to contact rollers or locking elements 38 are crowned and are mounted on and in the rotary disc 8 secured to the stub shaft 1, in seats adapted as described with reference to Fig. 2 for the balls ill. The radially adjustable rotary disc 39 is provided with an inverted plane conical recess 40 forming a counterface for the roller '38"so'afs'to ensure a smootlr' transmission. The disc 39 is displaced, for the purpose of changing the transmission ratio, parallel to the generatrix M; the operation of this form of gear otherwise is similar to that of Fig. 1.

The design of my present speed-changing gear also may be such as to permit of applying the locking action only in the one sense of rotation of the disc provided with the recessed seats for the rollers. Further, e. g. with reference to Fig. 4, the ball seats l8 may be disposed in chords instead of radially as shown.

What I claim and desire to secure by Letters Patent 1. A mechanical; infinitely variable change speed gear, comprising at least two round ro'ta' tional' discs disposed eccentrically with respect to each other", one of' said'discs'having an" annular series of locking roller members disposed thereon concentric with the axis" of said one disc. the axes of said two rotational discs beingdisposed obliquely with respect to" each other, the said annular series of locking roller members being in power transmitting contact with the other rotational disc; and mechanical means connected with one of the rotationaldis'cs'for effecting" rel ative radial dis'placem'entof the latter said one of the rotational discs with respect to" the axis or the other rotational disc:

2. Mechanical infinitely variable change s eed gear comprising two round' rotational dis'cs' dis: posed coaxially to other; each of said discs having an anmuar eries of locking roller mnT- brs disposed concentric t-e the axis" or their re: s'pectiv'e disc, and a round middle disc dispos'd betweenthe aforesaid two fm'itz'itior'ialldiscs are eccentri'c'ally dispo'iseillwith rf'spect to their com; mon axis. said middl'i disc being disposed ob liquely to the tw q bther fe'tational discs said 015 lique disc being laterally engaged inpowef trans m'itting C ntact with the two afifiuiar' series 6: locking roller member's. tearing retains mounted on said i'nid" 1e guide for mtymg aiag ariiig and said iii'iadie disc radially of said initiate islethe' eccentric t:- sition of thje midl'e dist; hin hereby varied respect to the two 4 .ieflgfrfl piaifio d t ltrl the (KING ratio Between the twt outer r'otatidiiai discs. 3

3. A change gear acjordiiigf tcilain'i' 2, and iii which one gf tlre rotational discs Provided with a series' of ldclging roller members is formed with teeth to constitute a: part (if a planetary gearing;

itiii eitizncii's cit'r'iiii The following references are of record in the file of this patent:

UNITED STATES PA'I'ENT'S Number Naffi et l... 1,146,982 Weiss July 20,- 1915 2,019,006 Ferrari Oct. 29, 1935 2,163,066 Searcy June 26, 1939 

